~ 12.8 12.5 ~W w i!i§ = W I~ 1111.0 Ii: liii. 2 2 ~W ~ 1111.0 2.2 . Iii ... ~ ... ~ &:. iii E ~ E ~ ...101 ...... " I " 1.1 1.1 WlAw.... I - 1111,1.25 1111,1.4 111111.6 1111,1.25 ""'1.4 111111.6

. "'

MICROCOPY RESOLUTION TEST CHART MICROCOPY RESOLUTION TEST CHART NATIONAL BURlAU or STANOAROS-1963.A NATIONAL BUREAU OF STANOAROS·1963·A 'l.1 5'"3-l ./~, GRASSHOPPER EGG PODS DESTROYED . BY LARVAE OF

BEE FLIES,

; t~ BLISTER BEETLES, .J7I • ~ G2 ~;~ AND GROUND BEETLES E-< -' -~ I- =:J ~ ~~ RFFEREt'.!CE ~ ~ - ~ ~' -~<: DO Ir:>T LOAt'~ ~y J. R. Parker art! Claude Wakeland

•

Technical Bulletin No. 1165 • Washington, O. C., July 1957

UNITED STATES DEPARTMENT OF AGRICULTURE • • ACKNOWLEDGMENTS

1Iost of the firld work OIl the 16 s(11clv areas was conducted by em­ ployees of the Entomology Research DIYision, and the data pre'sentecl were takrIl from the'ir field notes and SUlllll1111-y reports. rrbey \\'ere' us follows: F. D. Butcher, E. G. Din-is, II. '\-. P]'('s('ott, G. T. York, A. 'Y. Buzieky, D .. Denning, P. Xicholsoll, J. R. Horton, O. L. Barnes, and C. C. Wilson. Tbose who took part in conducting SutTey-s of the grassland regions wore: C. O. Essclbaugb, F. A. 1Iorton, R. C. Xewton, and L. Seaton. The control sUlTey data ",-ere obtained by 132 snpelTisors and assistants aSP

CONTENTS Page Summary...... 1 Scope of the study...... 3 Sources of data...... 4 Methods of obtaining and using data...... 4 Analysis of data collected in connection with research studies ...... 6 Grasshopper egg pods destroyed in predominantly cropland areas...... 6 • Summary of p 'edatism by larvae of btle flies, blist,~r beetles, and ground beetles on study areas...... 15 urasshopper egg pods destroyed in predom·'.iantly grassland areas...... 15 AnGilysis of data collected in connection with control suJ'veys ...... 17 Predator species and distribution records...... 25 Di<.'cussion ...... 27 Literature cited...... 28 ji • ., ~ ! I t •

Grasshopper Egg Pods Destroyed by Lart,ae of Bee Fli,~s, Blister Beetles, and

G/I'ound Beetles 1

By J. R. PARKER,2 EntomolollY Research Division, and CLAUDE WAKELAND, Plant Pest Control Division, ltgri(:1tltvr{[l RC81laTch Service

SUMMARY Data are pt"esentocl to show the percentage of grasshoppei' egg pods destroyed b)~ larvae of br.e flies (Bombyliidae), hlister beetles (lvieloi­ dae}) and ground bee tIes (Carn.bidM). • The data were obtaiilcd in annual grasshopper egg surveys made on 16 study n.reas in 7 Stntes (3 stud.\' lLreas in ArizonlL, 2 in Cnlifor­ nia, 2 in Kansas, 1 ill :Millllcsota, 4 in 1Iontana, 3 in Korth Dakota, and 1 ill South Dn.li::otlL), and in grasshopper egg surve~'s made for use in control work in aU the ,\1'"este1'1l iLlld ~liclwestern States in 1938, 1939, and 1940. Other daLtL \\'ere oblnined in ltnllual grasshopper egg surveys of six counties in Cnlifol'llitt alld of the ll1njor grnssland arens in Montana, Xebraslm, Korth Dn.J.:oln" South Dnkotn, alld ,\V~'oming. Surve\Ts of the J(j sLuc!\' m:cns and the 6 California counties were made on cropland and adjaccnt, grassland. In the sUITeys of the western g1'n.ssln.nd rcgion, all soil samplcs takcn were remote from crops. ;';Ul'ycys in C0I111CC1l011 \\'jtll grasshopper control work were made Oil cropland, eXtept; in n, fe"" instalJces where nLllgehLnd imme­ diatel.\' n.djnecnt 10 crops was examined. The number of sound grasshopper egg pods, dest.royed pods, and pt'(>datol's pct' squllxe root \\'ere determined by sifting soil from a Sf( ual'e-foot aren.llu·ough n. quarter-inch mesh scrCOIl. Appl'oximatel.\T 36,000 soil samples \\'('1'0 examined in reselLrch surveys aud 202,000 • in control smveys. The percent.age of the egg-pod populn.tion de­ st.royed b~' each predator was obtn,inccl hy dividing the number of pods destroyed hy ('neh kind of predator by t.he numher of egg pods per square foot. The average mltlllnl destruction of egg pods for the 16 study areas as n, group was 17.87 perccllt (6.18 percent. hy bee flies, ~.80 percen1. by blister bectles, nnd 2.89 pct'cent by ground heetles). rhe average total nnnual pl'cclatism, h.\' Sin,tes, wn.s: North Dnkota, 27.G2 percent; Montana, 25.30 percent; 1:iinncsotn, 21.7:3 percent; South Dakota, 18.63 pel'ceJlt; California, 16.01 percent; Kansas, 10.49 percent; and Arizona, 5.30 percent. Highest destruction of egg pods in a single area in each State for n, single yom' Wl),S as follows: Dickinson, N. Dale, 77.52 percent in 1939; San Luis Obispo, Calif., 60 percent

I Submitted for publication November 29, 1956. 2 Retired June 30, 1954 . • '\ 193i;\ravre, Mont., .55.55 percent in 1940; lIitchell, S. Dak., 32.70 percent in 1939; Hallock, :Minn., 30.0 percent in 1941; Hays, Kans., • 25.00 percent in 194"; and Tempe, Ariz., 16.6i percent in 1939. The average aIlnual destruction of egg pods in the 6 counties in California \\'as 27,6 percent; highest prednJism in a single county for a single year was 5!J..50 percent in San Luis Obispo County in 193i. The average annual ckstruclion of egg pods in the grassland areas of ~{ontana, Kebraska, North Dakota., South Dakota, and ,Yyoming was 5.10 percent (l.80 percent by h.'e flies, 2,90 percent b"T blister beetles, and 0040 percent by ground beetles). Highest total destruc­ tion in a single y('ll,[, ,,"as 9.50 percent in 1944. Predatism was con­ siclerabl)T lowcr ill t.he grassland al'('l\'s than on cropland in stud,)' areas in the same States. Habitat pmferencC's of l)l"('(latol':'; 011 stud.\" lLrC'as \"ere sometimes pronouneed but \\"ere not consistent for all arN1.S or all years. There \nl,s a general lenelt-nc,'" toward fl, high pereentage of pl'edatisl11 during ,\"ears of high egg-pod populn,tion, hut this did not hold true either for all stud," areas or for all ,"rars. Grasshopper egg surveys \\"ere 'made n.nnually as a part of the • Grasshopper Control Project to l1('lp determine the infestation to be expected the followillg ,n'at'. P;nrlings from such Slll'Ve.,"s formed the bn,sis for pli1lming for' the neXI: .n'n,l"s contl'Ol needs. ,Vhen this stud, ,,"n,s begun, the expectn.tion was to n,lull.':ze the datu. accumulated since the Project was established in ] 938. After 1940, however, the smvey records larked dnta essentin.l to cn.lculn,ting percentages of preclatism, so n.nal.,"sis of eon trol SUlTe.\- dn,ta was confined to the years 1938, 1939, and 1940, The averagl' n.nl1ua.l dest.ruct ion of egg pods for the 3 ,Yen.rs, as de­ termined by the control project SUITC.'", Wfl,S 15.0 percent (6.9 percent hy bee flies, 5,G percent b.," blister heetlcs, n.nd 2.5 pe['eent b:--- ground hecHt'S). The n,vel'nge i1IlIlun,1 percentage of eggs destro,\"ed h:,>- preda.­ tors in tIll' 5 Stn.tes where Slll'vey was tl1(' most complete for n,U 3 .'-et1.J"S \\"as as follo""s: North Dn,].::ota, :32.5 perel'nt; Colorado, 23.,1'. percent; South DakoUL, 22.9 percent; Xehmslm, 1(1.4 percent; and ~[ontl1.na, 15.9 percent. Average preclatism ,,-as 50 percent or 11101'(' in many counties in seycml Statrs each year. Highest destl'uetion of egg pods for eacb vcar was as follow's: . AmzoNA-5Pi percent ill Santa. Oruz Count,y in 19:39. • COIJOTIADO-60 peTcent in Kiown County in 1938; 55 percent. in Bent County in 1940. hrx,'mIS~50 prrcC'nt in Schuyler Oounty in 1939. ~rlXXESO'l'A-67 prrcent in Dnkota Oouuty in 1940. :,{0~'I'Al'B-59 percent in Riehlnncl Connty in H):39; 50 percent, in Hill and Prairir Counties in 1940. NEBRASKA-56 percpnt in Sheridnn County in H):38; 50 percent in Seotts Bluff Oount)T in 1939; 5:3 percent in Knox County in 1940, NOll'l'H DAKO'.rA-GO percent. in Benson, Foster, and ~IcKenzic counties in 1938; G5 percent in ~'[cKenzic County in 1940; 53 percent in :,:fercer Oounty in H)39. OKLAHO;\fA-59 pCl'eent in Cimarron County in 1938. SOUTH DAKO'1'A-64 percent in Perkins County in 19:38; 63 percent in Bennett County in 1939; and SO percrnt in Butte Oounty in 1940, TEXAS-52 pC'rcent in Carson County in 193,s, TTTAH-64 pE'l'ccnt in On,rhon County in 19:j9, 2 • WASHIKGTON-50 percent ill Ferry County in 1939. The most common species of grasshopper egg-pod predators encountered were the follo\\'ing: • n1eloidae-Epicauta macula.ta (Say), E. puncticollis (Mann.), and E. fabl'ic'/,i (Lec.). Bomb'liliidae-Systoechilts mdga.l'is Loe\\' and Aphoebantus hirsutus (Coq.). Carabidae-Amal'a obesa (Suy) and A. hesperia (Csy.).

SCOPE OF THE STUDY

I.1arvae of bre fIirs (Bombyliidae), blistrr beetles (?\Icloidae), and ground beetles (Carabidae) were listed as predators of grasshopper egg pods in the Unil,ed Statrs b:y Riley in 1878 and 1880 (4, 5).3 Since then, many rnL()mologists have mentioned them as important insect enemies of grassllOpprl's. In most of these references the percentage of the grasshopper egg-pod population destroyrcL is 110t stated, but Criddle (1), "',Tilson (7), Shotwell (6), and Gilbertson and Horsfall (2) have published qlHtnlitative data showing that these predators arc • capable of destroying large segments of gmsshopper egg-pod populations. Criddle statpcL thut thr combined effects of Sysloech1ls 'lmlgaris Loew, several sprcil's of blister bertle, and carabicL laryar destroyed over 20 percrn t of til(' grasshopprl' rgg pods in the rntire Province of ~Ianitoba in 10:32, and in some areas rgg drstmction reachrd fully 90 Drl'Cent . .' \Vilson found that iH'e fly larvae drstro:yrd 44.5 percent of the egg pods in ('ammda pdlucirla. (Seudd.) rgg beds Mar Tulelake in 110rthrrn Californiu, in 1\)2\). .No otbrl' predators W0re found. His records arc based on 5 soil sam pies taken on eaelt of 7 egg heds. The ('gg beds ranged in sizr from 2 to 2\J aen's, and eaeh soil sample WflS from a 1-square-YfLrd urea. Shotwell published an uccount of the grasshopper egg-pod preclators found in the egg sm'vey conducted us n part of the Gmsshopper Control Project in the fall of 19:38 by tbe Entomology Research Division and cooperating States. Records were obtn.ined on a total of 6,277 fields it) 11 States. The numbr,r of predators per square foot of soil were: Bee fly larvae, 0.31; blister heetle larvae, 0.24; and ground beetle lUrYllr, 0.06. In lll'ens \\'I1err bee fly lan"ae were • most numerous, from 20 to 70 prrcrnt of the egg pods were destroyed. Gilbertson and Horsfall found 59.:3 prrerut of a l\lelanoplus mexi­ camus me:J;ican1lS (Sauss.) egg population in South Dakota destroyed by predators in U)38 (;35.6 percrnt hy bee fly larvae and 2:5.7 percent by blister heetle larvae). Tbeir findings were based on] 00 soil samples (each from a l-square-foot nrra) taken at random in 80 acres of wbeat, stubble. Tbe Entomology Rrseareh Di\'ision and thr Plant Pest Control Division have not conducted detailed studies of the biology of grass­ hopper egg-pod predators. However, in the annual grusshopper egg­ pod surveys numerous records haye heen Illade of the percentage of egg pods destroyed by bee flies, blister beetles, and ground heetles.

3 Italic numbers in pl1l'C'nthcsps 1'(,[(,1' to Literature Cite'd, p. 28. • 3 Because of the importance of tl1('se predators in any study of grass­ hopper populn,tions and the rehltively few pre\~iously published • quantitative data concerning them, the records, even though most of them arc more than 10 yenTs olel, have hren assemhled and m'e presented in this bulletin,

SOURCES OF DATA The data conected by the Entomology R{'seal'ch Division were obtained in 7 Stutes on 16 study lu:rn.s estahlished for the pUl'pose of conducting yeaTl~- ecological [,;tuclies of grnsshoppers, including intensive sampling of the egg-pod popula,tions in n.11 the major habitats on each fI;rea. The study axeas "-ere set up in C1'op-gro,,-ing distri~ts subject to grasshopper outhreaks and included crops and range plants representative of those. found on surrounding farms. Each area was about 4 miles long and 2 miles ,,-ide. Other research da.ta were obtained by the Entomology Research Division in conn.ection with grn.sshoppel' egg-pod surveys of the major gmssJand areas m several Western States. The dnta collected by the Plftnt Pest OontrolDivision were obtn.il1ed in n.nnun.l grrrsshopper' egg-})od slllTeys of 'Western n.1Hl ::\1idwestl.'rn • Staies to cleterminl.' where grnsshoppers were numerous enough to indicftte they might ne('(l to be controllec1 the following yeur. In 19:38,1939, and 1940, reeol'ds for en.ch sUJ:vry stop showed the number of egg pods found find thl.' nmnbrr of porls clestro)'ed by bee fLies, blister beetles, find ground beetles. From this informlltion in the original field notes it. WftS 1)Ossib1e to cn.lculate the percentage of egg pods destroyed by rn.eh kine1 of precintor anel the total1)ercentnge of l.'gg pods eneh dest.royed. Unfol'tunn.lrly, prrcentnge figures could no longer be derived after 1940 becn.lIsc' of curtalIment of pm'sonnd engfiged in grnsshopper c;uryey ,\"ork.

METHODS OF OBTA!NING AND USING DATA The number of grnsshopper egg pods nnd the number of predntors per squnl'e foot wern determined by sifting soil from n squure~foot firea t.hrough n qunrter-inch mesh screen and recording the number found. 'I'he duta in this pilper were based on npproxima tel~T 238,000 soil sn,mplcs (36,000 inken in Tescftl'ch studies nnd 202,000 in control surveys). • A record wus mn.c1e of sound grnsshopper egg pods, preclator-infested egg pOlls, ftnd unftttachecl predators found in each soil sample exam­ ined. These three items ndded together represent the t.otnlnumber of egg pods per squflre foot of soil. The number of preclntors per square foot was t.he sum of those founel in egg pods and those found free in the soil. A record wn.s mn.de also of the number of bee flies, blister beetles, amI ground bl.'etles (larvae and pupne) making up the predn.tor population. Other insect predfttors \wre Hever found in sufficient numbers to affect the egg-pod population matl'rilllly, and they were disregarded. The percentage of the egg-pod populn.tion destroyed by each predator was obtained by dlyiding the lllllnber per square foot by the totn.l number of egg pods per squnre foot. This method of computing t.he totnl number of grnsshopper egg pods per square foot and the percentage of egg pods destroyed by 4 • each predator is hRsecl 'on three assumptions: (1) One predator­ attacked poel contains only one predator; (2) one predator ill an egg pod will completely destroy that pod hut will not attRck another; (3) • one predator found free in the soil has alreRdy destroyed one egg pod. The first assumption is not always correct. Sometimes more than one l)redator is found in an egg pod, but such pods are unusual. Personnel with long e:\.-perience in grasshopper egg sunreys agree that less than 1 percent of predator-attacked pods cont.ain more than one predator. The second assumption is based on field e:\.-perience and some e:\.l)erimental results. Spring surveys show nearl:r complete destl'llC­ tion of all eggs in predator-infested pods as compared wiLh a smRller proportion of eggs destroyed in pods fOlll1d during surveys in the same location the previous fRll. "Wilson (7) states that unconsumed eggs in Cammlia JJellucida egg pods containing bee fly larvae failed to hatch when held in the laborl1lory anel therefore should be con­ sidered destroyed. On the other hand, Horsfnll (3) hns sho,,"n that the second l'ssumplion is not ahYlLYs correct,. He found that several species of hlister beelle lalTne consumed from 25 to 45 .llfelan01Jlus diffel'entialis (Thos.) eggs dming their entire feedjng period when • they" were allo,,"ed to feed to replelion. This indicates that a single blister beetle larva is capable of destroying the enti re. contents of egg pods of such gl'nsshopper speciC's os C. pellucida and ill. mexicamls mc:ricanus, which selclom contain more than 30 eggs per pod, but only pnrt of the 75 to 100 eggs llsnally found in 1\1. dijferentialis and 111. bil'iltatlls (Bay) egg pods. Horsfall apparently assumes that uncon­ sumed eggs in pods attacked by blister beetle lnlTilC hatch normally, bu t ,Vilson's results indicate thnt such mny not be the case. The nssumption tlUtt fl. single predn.tor does not nUnck more than one egg pod may not hold true for ground beetle lHlTae, whjch nre free moving, but there are no claLa to show how mnny eggs one lnnra can destroy. Bee flies and blister beetles lack functionnl legs in their Into. larYRl stages nnd cannot move more thnn it few inches in search of egg pods. ,Vhere egg pods are packed closely together it might be possible for one larva to destroy an ogg pod and then enter another, but no concrete example of this has been reported during the man:r yenrs that egg-pod surveys have been conducted. The third assurnption is bnsed on the filet that both beo fly larvae and blister beetle lnrvnc frequently burrow below 01' to one side of the • egg pods nIter destroying the individual eggs. The remnins of egg pods whose contents hl.ve been eaten nre eRsily broken in the soil­ sifting process nnd cnnnot always be recognized ns inclividual pods associated with It parliculnr predator. Therefore, every predator found free in the soil is creclited 'with destroying one egg pod not previously counled. This Rssumption is nlso subject to error. Hors­ fnn, ns nirendy mentioned, hns sho\\"n that blister beetle lnrvoe may complete their feeding and Ie/we the egg poels without consuming all the 75 to 100 eggs of such grnsshoppcr species as 11£elanoplus cliifer­ entialis and 111. bivittatus. It seems likely that It single bee fly lnrva would also fnil to consume all the eggs in an egg pod of either of these species. This would oycrcmphosize the importance of predators in regions where JM. cli:tferentialis anclllL bivittatus are clominnnt. All the mo.jor chanees for error in the method used for determining the percentage of egg pods destroyed by predators tend to overmte their importance, but this is more than counterbalanced by the fact • 5 that considerable numbers of predators are overlooked in the soil­ sifting process. It is It laborious and painstaking task to recover and • count grasshopper eg~ pods; to find their predators is even more difficult. E!1rly larval stages can be found only by microscopic examination of the soil sample, and this is impracticable in the usual grasshopper egg sm·vey. L!1te larv!11 stages and pupae are smaller than grasshopper egg pods, and many of them undoubtecll}' pass through the screen unnoticed. Bec!1use of the certainty that con­ siderable numbers of pl'edlttors are oyerlooked in soil sampling it is believed that the records presenteclactu!111y underrate their importance by at least 5 percent.

ANALYSIS OF DATA COLLECTED IN CONNECTION WITH RESEARCH STUDIES

Grasshopper Egg Pods Destroyed in Predominantly Cropland Areas The qUHntitativc. dat!1 include records for indiv-idual study areas for periods l'nnging from 2 to 10 years. It would be cumbersome and • does Dot 8('em worthwhil(\ to pl'('sent yearly records for all areas. rrherefore, they hayc h('en summarized and grouped by States. (Sec table 1.) Arizona Records from lhizonll ar(\ aVllilnblc for study areas at Tempe, Yuma, and Chino Valley (tab1e 1). The Tempe and Yuma areas are in southern A.rizona Ilt elevations of 1,159 and 110 feet; they include irrigated cropland and d('sert; prineipnl crops are alfalfo, and cotton ILt Tempe flnd alfalfa at Yuma; dOllunont gra,sshopper species are lvlelanoplus diiJerentialis and 1\1. mexicanus mexicanus. The Chino V!1Iley study orca. is in northel'l1 Arizona. at a.n eleva.tion of !1bout 5,500 feet; it includes croplaud surrounded by grassland; principal crops are beans, slllnU grains, and alfalfa; dominant grasshoppers aTe 111. lalcinus (Scueld.) and 1\1. mexicanus mexica1w,s. Destruction of grasshopper egg pods by predators WIlS lower on study areas iu Arizol1!1 than in auy other State where records were kept. The averuge annua1 destruction of egg pods totaled 5.30 per­ cent (0.4 percent by bee flies, 1.76 perc,mt by blister beetles, and 3.14 • percent by ground beetles). Only in Arizona and ol1e other State (1Jinnesota) was predatism by ground heetle larvae higher th!1n by either hee fly l!1rYae 01' blister bectle larvae. Highest destruction of egg pods ill Arizona in 1 year 011 1 stuely area was 16.67 percent in 1939 on the Tempe study !11·ea. California C!1lifornia records on grasshopper egg-pod pred!1tors include records made on study areas at Sacramenlo and S!1n Luis Obispo and in 7 counties subject to grusshopper outbreaks (table 1). The Sacramento study area is in Lhe central coast!11 region and hus an elevation of 50 feet; it is in an intensely famwd, irrigated river valley; princip!11 crops are alfalfa, sm!1H grains, 11nd truck crops; dominant grasshopper spe­ cies arc lItlelwtWphts ma,rginalus (Scudd.) and J.l1..femul·-rubrum (DeG.). The San Luis Obispo study aretL is in the southern coast!11 region at an 6 • elevation of 300 feet; it is composed largely of rangeland but. includes some smull grains and cultivated crops; dominant grasshopper species are Oamnula pellucida and Oedaleonotus enigma (Scudel.). Records • of egg-pod predators were obtained from general surveys in the follow­ ing counties: Imperial, Sacramento, San Diego, San Luis Obispo, Santa Barbara, and Ventura. Imperial County is in the southeastern corner of the State; all the others are in the southern coastal region. Dominant grasshopper species arc j\1.. mexica,nus mexica,nus in Im­ perial County, fl.1.. ma,rginal1ls in Sacramento County, and O. peUucida, ill all other counties. Average annual destruction of egg pods totaled 16.01 percent (1.71 percent by bee flies, 14.13 percent by blister beetles, and 0.17 percent by ground beetles). On the Sacramento area prrdatisrn was higlwst in 1938 when 26 percent of thc egg pods were destroyed by blister beetlc larvae, the only predator present. On the San Luis Obispo area predatism was higlH'sL in 1937 when 60 percent of the rgg pods were destroyed (48.9 percent by blister beetles and 11.1 percent by bee flies). No bee fly larvae were reported for th(' Sacrftmenio area and only small numbers were reported for the San Luis Obispo area. This is in sharp contrast to the destruct;ion of 44.5 percent of Oammlla • pellllcida egg pods hy hee fly larvae ncar Tulelake in northern Cali­ fornia in 1929, reported by IYilson en. Ground beetle larvae were ('xtremel\T scarce 011 both study areas. C. C. 1,\'ilson, ,vho made the"' survrys on the two study areas in Cali­ fornia, assisted Sta,te p<'rsolllll'l in the county grasshopper egg surveys aud assemhLrd numerous county ]"('cords of egg-pod predators. Grouud hectic In,rvae were eonsidel"l'd too scn.I"CC to be worth recording. a.nd only the combined number of hee fly lan'ae nncl blister beetle larvae were listed. These' data, W('I"(, not as carefully obtained as the data on the stuely areas, but Lhry show the comhined ef-rects of bee fly and blister beetle larvae over larger arens. Therefore, they are presented in tn,bIe 2. The average annual destruction of grasshopper egg pods by bee fly larvae and blister beetle larvae for the group of 6 counties was 22.7 percent. This is 6.7 percent mor(' than wer!', (lestroyed by these two predators in the Sacramento and Sn.n Luis Obispo study areas (table 1). Preclatism was highest ill San Luis Obispo County with a 3-yeo,r average of 38.5 percent.. This county also had the highest percent­ age of egg pods destroyed in a single year-59.5 percent in 1937. Ventura County was second with 4:3.2 percent in 1934, and San Diego • County was i), close third with 42.9 percent in 1944. In all the Cali­ fornia surveys, egg-pod predators were most ahundant where Camn1da lJelhwida wus the dominant grasshopper. Kansas Kansas records on grasshopper egg-pod predators are from study areas at Hays and Garden City (table 1). The Hays area is in cen­ tral Kansn,s at an elevation of 2,000 feet; wheat is the main crop; ll1elanoplus me;l;icanus me:m'canus is the dominant grasshopper. The Garden City area is in southwestern Kansas at an elevation of 2,836 feet; small grains, sorghums, and legumes are the main crops; fl.£. mexicanus mel;icaml8, 1\1. bi'villalus, fl.1.. (lijJerentialis, and fl.£. jemur­ 1'ub7'um arc the dominn,nt grasshopper species. Average annual destruction of egg pods totalecl10.49 percent (6.55 percent by bee flies, 3.66 percent by blister beetles, and 0.28 percent • 422168-57--2 7 01) TAnLl~I.-Grasshopper egg pods destroyed by larvae of bee flies, blister beetles, and ground beetles on study areas in Arizona, Oalijo1'ltia, I(ansas, l11innesota, lVontana, North Dalcot(L, and So'u,th Dakota

Average percentage of pods Average Average destroyed by­ samples pods State and study area Sun'eys per per year square Bee Blister Ground All foot fly beetle beetle larvae larvae larvae larvae

Arizona: lVlt/llber Years N1lmbcr Number Percent Percent Percent Percent Tempe, Maricopa County______3 1937-3!L ____ 595 0.08 O. '16 1. 73 5. 75 7. 94 Yuma, Yuma County______3 ]937-39 ______209 .25 0 0 .87 .87 Chino Valley, Yavapai COUl1ty___ ---- ______4 1937-39; 19'1L 328 .21 .66 3.11 2.89 6. 66 Average (weighted) ______------.._------372 .18 .40 1.76 3. 1<1 5. 30 California: Sacralllento, Sacramento County______6 H):~G-4L _____ ] 23 .98 0 17.30 .16 17.46 1936-45______San Luis ObiSpo, San Luis Obispo County_o __ 10 395 ~.23 2. U 12. 24 .18 15.16 Average (weighted) ______------293 1. 76 1.71 l4. 13 .17 ]6.01 - Kansns: Hays, Ellis COUllty ______5 1942; 1946-49_ 125 .05 10. GO 2. ]0 . '10 13. 10 Carden City, Finney County______5 1945-'19______250 .19 2.50 5. 22 .16 7.88 Average (weighted) ______------187 .12 6.55 . 3.66 .28 10.49 Minnesota: Hallock, Kittson County______3 1939-4L _____ 540 .57 5. 00 7.10 9.G3G

• • • • • • • • Montana: Brinkman, Hill County______7 1939-45______184 .34 3.13 13.33 .76 17.22 Gildford, Hill County______7 1939-45______150 .33 10.27 18.64 1.07 29.98 Havre, Hill County______7 1939-45______186 .62 12.49 20. 88 4.44 37.81 Huntley, Yellowstone County ______7 1939; 1941-46_ 269 .19 5.30 9.80 1. ]4 16.24 Average (weighted) ______------197 .37 7.79 15.66 1.85 25. 30 North Dakota: Beach, Golden Valley County______8 1939-46______242 .61 12.59 12.80 3. 70 29. 09 Dickinson, Stark COllnty______8 1939-46______208 .32 14. 22 13.08 .81 28. 11 Mandan, Morton County______8 1939-46______283 .36 8. 87 14.69 2. 13 25. 69 Average (weigllted) ______------244 .43 11. 89 13. 52 2.21 27.62 South Dakota: Mitchell, Davison County______9 1938-46______204 .48 9.90 5. 79 2. 94 18.63 Average (all States) ______------.56 6.18 8. 80 2.89 17.87

04 TABLE 2.--(}rasshopper egg pods destroyed by bee fly larvae and blister beetle lar'uae combined, as determined in county grasshopper egg surveys • in California . Average Average Average samples pods per percent- County Surveys per square age of year foot pods de­ stroyed

Nmnber Years Nmnber Number Percent ImperiaL ______1 1937 129 1.4 11. 2 Sacramento______2 1936-37 185 .45 16.4 San Diego ______4 1936-37; 182 11.8 23. 1 1944-45 San Luis Obispo ______3 1936-37; 424 1.8 38.5 1939 Santa Barbara______2 1936-37 90 1.5 10. 8 Ventura______4 1934-37 31 2.2 22.2 Average (weighted) ____ ------175 4.2 22.7 by ground beetles). This was the lowest recorded for any State ex­ • cept Arizona. It may possibly be explained by the fact that grass­ hopper egg-pod populations were extremely low during all the 5 years for which records were kept. Low egg-pod populations not only decrease the actuall1umber of predators but also tend to reduce the percentage of egg pods the predators destroy. The highest record of predatism in Kansas occurred on the Hays study area in 1947 when bee fly larvf'oe, the only predator found, destroyed 25 percent Df the egg pods. Minnesota Records of the percentage of grasshopper egg pods destroyed by predators were kept for a study area near Hallock (table 1). This area is in northwestern :Minnesota at an elevation of 815 feet; wheat and sweetclover are the main crops; 111.elanoplus bivittatus, M. mexi­ canu.s mexica1lftJ,s, and Camnula pellucida are the dominant grasshopper speCIes. Average annual destruction of egg pods totaled 21.73 percent (5.00 • percent by bee flies, 7.10 percent by blister beetles, and 9.63 percent by ground beetles). Minnesota was the only State in addition to Arizona in which predatism by ground beetle larvae was higher than by either bee fly larvae or blister beetle larvae. Predatism on the Hallock study area was highest in 1941 when 30.0 percent of the egg pods were destroyed (13.1 percent by ground beetles, 8.0 percent by bee flies, and 8.9 percent by blister beetles). Montana Records of grasshopper egg-pod predators are from study areas at Brinkman, Gildford, and Havre in north-central Montana, and at Huntley in south-central Montana (table 1). Havre is 30 miles south of the Canadian border and has an elevation of 2,480 feet; Gildford is 30 miles west of Havre; Brinkman is 20 miles southwest of Gild­ ford; elevations at Brjnkman and Gildford are about the same as at Havre. Dryland small grain crops and native prairie vegetation oc­ cupy most of the land on the Brinluuan, Gildford, and Havre study 10 • areas. Huntley is in the Yellowstone Valley at an elevation of 3,000 feet; principal crops on the study area arc irrigated small grains and sugar beets; prairie range vegetation and irrigated pastures are also • included. Melanoplus mex·icanus mexicanus was the dominant grass­ hopper on all the study areas. Average annual destruction of grasshopper egg pods totaled 25.30 percent (15.66 percent by blister beetles, 7.79 percent by bee flies, and 1.85 percent by ground beetles). Highest predatism for single years in each study area and the percentage of egg pods destroyed were as follows: Brinkman, 31.2 percent in 1945 (26.7 percent by blister beetles, 4.1 percent by bee flies, and 0.4 percent by ground beetles); Gildford, 53.3 percent in 1943 (27.3 percent by bee flies and 26.0 percent by blister beetles); Havre, 55.55 percent in 1940 (30.41 percent by bee flies, 22.55 percent by blister beetles, and 2.59 percent by ground beetles); and Huntley, 34.6 percent in 1939 (23.5 percent by blister beetles and 11.1 percent by bee flies). Records of grasshopper egg pods destroyed by predators in the major habitats on the study areas at Brinkman, Gildford, and Havre were obtained for the 6-yen,r period 1941 through 1946. The data • have been summarized and are presented in table 3. TABLE 3.-Grasshoppe1' efJ(J pods destroyed by larvae oj bee flies, blister . beetles, and groun(l beetles in the mador habitats included in the study areas in north-centTal ]..([ontana 1

Average percentage of pods Average destroyed by­ pods Habitat per square Bee fly Blister Ground All foot larvae beetle beetle larvae larvae larvae

l{urnber Percent Percent Percent Percent Field margins______0.60 7. 96 9.18 O. 89 18.03 Idle land______.41 5. 08 12. 02 9.55 12.65 Small grains ______.24 14.29 11. 70 0 25.99 Rangeland______.25 0 22.51 .19 22.70

1 Averages for the 6-year period 1941-46 on study areas at Brinkman, Gild­ • ford, and Havre. Predators as a group destroyed considerable numbers of grasshopper egg pods in all major habita,ts in Montana, but no egg pods destroyed by bee flies were found in rangeland and none destroyed by ground beetles were found in small grains. Bee flies were most effective in small grains, blister beetles in rangeland, and ground beetles in idle land. The 7 years of continuous records for the study areas in Hill County afford an opportunity to compare the percentage of egg pods destroyed in years when the egg-pod population was low with the percentage destroyed in years when the egg-pod population was high. Compari­ sons are shown in table 4. For the Brinkman and Havre study areas and for all areas as a group, the average percentage of predatism wa.s higher in the 3 years of rughest egg-pod popula.tion than in the 3 yea.rs of lowest population. • 11 TABLE 4.-Grasshopper egg pods destroyecl by predato1's on study areas in H1:ll County, Mont., in'the 3 years oj lowest egg-pod population and • in the 3 years oj highest egg-pod population

Years of lowest egg-pod Years of highest egg-pod population population Study area IPods per Percent- Pods per Percent- Year square age de- Year square age de­ foot stroyed foot stroyed ------Number Percent Number Pc,'cent 943 O. 26 2. 30 1941 O. 71 16. 60 Brinkman______1944 .22 1. 30 1939 .47 28.00 r1945 .11 31. 20 1940 .33 21. 80 Average______-----­ .19 11. 60 -----­ .50 22. 13 942 .27 17.50 1940 .62 29.90 Gildford______1943 .25 5:3.30 1939 .51 32.50 r1945 .08 34. 70 1944 .28 17.00 • Average______-----­ .20 35.16 -----­ .47 26. 46

IIavre______942 .18 41. 86 1940 2.66 55.55 1944 .15 19. 61 1939 .87 32. 18 r1943 .06 20. 20 1941 .21 46. 94 Average______-----­ .13 27.22 -----­ 1. 25 44.89

Average (all areas) __ -----­ .17 24. 66 -----­ .74 31. 16

This did not hold true for the Gildford study area, where the highest percentage of predatism occurred during the 3 years of lowest egg­ pod population, nor was it alwu.ys true for the Brinkman and HaVl'e study areas when records for only 2 years were compared. North Dakota Records of grasshopper egg-pod predators are from study areas a.t. Beach and at Dickinson in southwestern North Dakota and at Man­ dan in south-central North Dakota (table 1). Beach is 3 miles east of the Montana State line and 62 miles north of the South Dakota • border; it has an elevation of 2,759 feet. Dickinson is 64 miles east of Beach, at an elevation of 2,543 feet. :Manclan is 100 miles east of Dickinson, at an elevation of 1,750 feet. Dryland small gruin crops, legumes, and native prairie vegetation occupy most of the land Oll all three areas. The dominant grasshopper species on u.11 three areas is usually Melanoplus mexicanus mexicanus, but it is sometimes out­ numbered at Dickinson hv }.If.. jemur-rubl'um and at Mandan by M. dijJel'entialis. Average annual destruction of &Tasshopper egg pods totaled 27.62 percent (13.52 percent by blister beetles, 11.89 ,. 'cent by bee flies, and 2.21 percent by ground beetles). The ~. .1 differs only 2.32 percent from the 7-year average of 25.30 per"'''-1t for the 4 study areas in Montana. Highest predatism for single years in ea.ch study area and the percentage of egg pods destroyed by each predator were as follows: 12 • Beach,76.16 percent in 1940 (49.74 percent by bee flies, 21.42 percent hy blister beetles, and 5.00 percent by ground beetles) i Dickinson, 77.52 percent in 1939 (49.08 percent by bee flies and 28.44 percent • by blister beetles); and IvIandan, 68.69 percent in 1IH3 (48.% percent hy blister beetles and 19.74 percent by bee flies). Records of grasshopper egg pods destroyed by predators in the major habitats on study areas at Beach, Dickinson, and ~Janclan for the 6-year period 1941 through 1946 arc sllmmnrizecl in table 5.

TABLE 5.-Gra88hopper egg 1)od8 de8lroYl'd by farml' oJ bee flie8, bli8ter beetle8, and ground beetle8 in the 111([:701" habitats 1~ncluded in the 8tudy at'ea8 in North Va/cota 1

Average percentage of pods destroyed Avel'llge by­ pods per Habitat square foot Bee fly Blister Ground All I l:uTtle beetle beetle lan'ae larvae larvae I • r Number' Percent Percent Percent Percent Field margins______0, 76 2. 23 3.67 2.71 8.61 Idle Iand______.70 3.89 5.56 .75 10, 20 ~ll1tlll grains ______.21 8. 97 U.O'l 4.05 24.5l Legull1es______.47 2.4S 10, OS 6.52 19. OS RangeIand______. OS 2.50 20.75 14. 44 37.69

~~"- - 1 Average for the 6-year period 19-11-,16 on study areas at Beach, Dickinson, and nIandan. Predators fiS. a group destroyed considerahle numbers of grass­ hopper egg pods in aU major hn,bitats. Predatisrn WfiS greatest in rn,ngeland. Bee flies were most effective in small grains, and both blister beeUes and ground beetles were most, effectiYe\' in rangeland. The 8 years of continuous records for study areas at Beach, Dick­ inson, and :ManchLll afl'ord an opportunity to compare the percentage of egg pods destroyed in ycal'S when the egg-pod populatioLl was l.ow with the pereenLage destroyed in yen,rs when the egg-pod populatlOll was high. Oomparisons arc shown in table 6. For each study aren, and for all al'Ct),s as [I, group, the average per­ • centage of predatism wns much higher for the 4 years of hig~est egg-pod population thfLn for the 4 years of lowest egg-pod populatlOll. However, this did 110t always hold tl'lle within a study area when records for only 2 yeurs were compHl'ecl, fiS will be seen in the following comparisons found in tn.ble 6: At Beach, the egg-pod population was 2.2-:1: per square foot in 1939 and pl'edatism wus 38.09 percent, whereas the egg-pod population was 0.99 per square foot in 1940 and predatism was 76.16 percent. At Dickinson, the egg-pod population was 0.05 per square foot in 1945 and predaLism was 3.05 percent, whereas the egg-pod popu­ lation was 0.02 per square foot in 1946 and prcdatisl1l was 6.25 percent. At Mandan, the egg-pod population was 0.12 per square foot in 1944 and predatism was 1.86 percent, whereas the egg-pod population was 0.02 per square foot in 1945 and predatisrn was 8.33 percent. • • 13 TABLE 6.-Grasshopper egg pods destroyed by predators on study areas in North Dakota. in the 4- years oj lowest egg-pod population and in the • 4- years of highest egg-pod population

Years of lowest egg-pod Years of highest egg-pod population population Study area Pods per Percent- Pods per Percent- Year square age de- Year square age de­ foot stroyed foot stro)ied

Number Percent Number Percent 0.29 36.52 1939 2.24 38.09 Beach,County ______Golden Valley ("421944 .26 11. 62 1940 .99 76.16 1945 .14 12.17 1941 .43 38. 22 1946 .11 11. 19 1943 .41 8.72 Average______-----­ .20 17.87 -----­ 1.02 40.30 .27 25. 29 1940 1.15 69.54 Dickinson, Stark County__ 1944 .05 14.05 1939 .43 77. 52 19'15 .05 3. 05 1942 .31 14. 87 • 1"" .02 6.25 1941 .30 13.86 Average______- -~:~:-I .05 12. 25 -----­ .55 43. 95 .19 13. '17 1940 .99 46.66 .:\Ialldan, Morton County__ 1944 .12 1. 86 1939 .89 43. 97 1'"411946 .03 7.68 1942 .38 14.88 1945 .02 8.33 1943 .29 68.69 , Average______-----­ .09 7.83 -----­ .41 4.3.55

A"erage (all areas) __ --­ .... _­ .11 12.65 -----­ .66 42. 60

South Dakota Records of gmsshopper egg pods d~stroyed by predators were kept for a study area at :Mitchell in Davison County (table 1). :Mitchell is in southeastern South Dakota and has an elevation of 1,293 feet; corn, small grains, ancllegumes are the main crops; j\1elanoplus mexicamls mexic(Llws, j\1. d~ffe7'ent-i(llis, and i\1. fem'll.l'-l·ubl'1.tm are thedominal1t grasshopper species. Average annual destruction of grasshopper egg pods totaled 18.63 • percent (9.90 percent by bee flies, 5.79 percent by blister beetles, and 2.94 percent by ground beetles). This was 8.99 percent lower than the average of 27.62 percent for the 3 study areas in North Dakot,fl,. Highest prcc1atislll in a single year on the Mitchell study area was 32.70 percent in 1939. This also was considerably lower than the rughest predatism for a single year on the North Dakota study arens. Records of grasshopper egg pods destroyed by predators in the major habitats of the study area at :Mitchell for the 6-year period 1941 through 1946 are shown in table 7. Bee flies were most effective in small grains and legumes; blister beetles and ground beetles were most effective in legumes. No egg pods destroyed by ground beetles were found in rangeland. 14 • TABLE 7.-Grasshopper egg pods destroyed by tar'cae oj bee flies, blister beetles, and ground beetles on the. modor habitats included in the study • area at Mitchell, S. Dak.! Average percentage of pods de- Average stroyed by­ pods Habitat per square Bee Blister Ground All foot fly beetle beetle larvae larvae larvae larvae

Number Percent Percent Percent Percent Fidd margins ______O. 90 2.00 1. 78 1. 67 5.45 Idle land______1. 24 2. 74 3. 22 2. 42 8.38 Small grains______.4.0 9. 00 8.00 4.00 21. 00 Legumes ______.90 8. 89 14.44 29.99 Rangeland______.44 1. 82 7.27 ---~~~~-I 9.09

1 Averages are for the 6-year period 1941-46.

Summary of Predatism by Larvae of Bee Flies, Blister Beetles, and Ground Beetles on Study Areas .A.verage annual destruction of grasshopper egg pods on the study areas as a group totaled 17.87 percent (8.80 percent by blister beetles, 6.18 percent by bee flies, and 2.89 percent by ground beetles). The average annual percentage of egg pods destroyed by each kind of predator in the State where it was most effective was as follows: Bee flies, 11.89 percent in North Dakota; blister beetles, 15.66 per­ percent in 1{ontana; and ground beetles, 9.63 percent in Minnesota. The percentage of egg pods destroyed by each kind of predator and by all predators as a group was highest in 11 solid block of States com­ posed of Montana, North Dakota, Minnesota, and South Dakota. Average annual predatism for this block was 23.07 percent, as com­ pared with a group average of 10.60 percent for Arizona, California, and Kansas. Arizona and Kansas had the lowest percentage of egg pods de­ stroyed and also the lowest number of egg pods per square foot . Grasshopper Egg Pods Destroyed in Predominantly • Grassland Areas Records of grasshopper egg pods destroyed by larvne of bee flies, blister beetles, and grouml beetles were obtained in 9 annual faU grasshopper egg surveys of the grassland region bounded by the 6,000- and 2,000-foot levels east of the Continental Divide and the 42d and 49th parallels. This region includes large grassland areas in 110ntana, Wyoming, North Dakota, South Dakota, and Nebraska. Dominant grasshopper species are 1\lelanoplu8 mexicanuB mexicanus, Ageneotettix deorum (Scudd.), Amphitol'n1l8 colomdus (Thos.), and Phoetaliotes nebrascensis (Thos.). Egg surveys were conducted each fall from 1942 through 1950. Survey stops were distributed as evenly as possible over the region. However, because personnel and time were not available to sample the vast acreage of lightly infested range, stops were made only where 5 or more adults per square yard had been found in earlier surveys. • 15 TAi3LE 8.-Grasshopper egg pods deslr-oyed by lanae oj bee flies, blister beetles, and ground beetles on g7"G-s8land areas in 111onlana, Nebm8!';a" • Jllortn Dakota, South Dakolcb, and fVyoming, 1042-50

A\'cragc pcrcen tage of pods A~'erage dcstroyed by­ pods per Year Samplcs square I foot Bee fly Blister I Ground All larvae beetle bectle larvae larvae I lan'ae - i 1942 ______lVu.mber Nu.mber Percent Percent !"'ercent Percent 1,962 O. 26 2. 9 3. 0 0.4 6.3 1943______~ ______1944 ______756 .30 2. 0 2. 5 .6 5. 1 1945 ______810 .31 2. 9 5.6 1.0 9.5 1946______540 .37 2. 9 5. 2 .3 8.4 1947______(384 .32 1.7 .3 .7 2. 7 1948 ______576 .21 .5 5. (3 0 6.1 1949 ______'J66 .21 1.1 1.4 0 2. 5 1950______738 . 56 1.4 .8 .2 2.4 954 .41 .7 2. 2 .6 3. 5 A verage ______• I 832 .33 1.8 2. 9 I .4 5.1 Eightccn soil smnplcs (en,ch from It %-squltre-foot. n,ren,) were exltm­ ined Itt eltch stop. The numher of egg pods found Itt survey stops undoubtedly WitS higher thltn the number present on other pm·ts of the mnge where smaller numbers of adults (less thltn 5) had been found in the em'lim' surveys. The avel'l1ge number of egg pods per square foot for the entire grltsslltnd region was eslimatedas follo\\'s: First, thl~ Itv-erage number of egg pods per squltl'e foot found during an egg survey was divided by the average number of adults per square Tard found Itt the same stops during the adult suryeys. This figure, which represents the number of egg pods pel' square foot produced by 1 adult per square yltrd, was then multiplied by the Itv-crage number of adults per squltre yard found dming the adult surveys for all sllJ've:y stops in the region t,o obtain the Itverage Illllnhcr of egg poels per squltre foot, as shown in tltble S. Totltl pl'eellttism by ImTn,c of bee flies, blister beetlet>. n,nd ground beetles did not exceed 9.5 percent in any of the!) years of SUl'V"ey, and • avemged only' 5.1 percent. This was lower thn,n for any of the 16 study Itreas. The fact L1mL most species of rn.nge grn.ssiloppers scatter their egg pods more \\'idely than species of crop grasshoppers, thus mn,ldng it more difficult for predlttors to find them, may be one reason for the lower percentage of egg pods destroyed in grn.sslands. This is in agreement with the faet that predatism on the study areas was highest during years of gren,test egg-poel numbers (tltble 5).

16 • Another possible explanation of the higher predatism in cropped areas is the fact that bee fly adults frequently gather in large numbers to feed on the blooms of annual plants growing on disturbed ground • along roadsides rmd fencerows, and swarms of blister beetle adults feed on legumes such as alfalfa and sweetclover. Having concen­ trated in such pl!1ces for feeding, it seems reasonable to believe they ,,-ould stay for egg laying. Predatism 1n tbe grassland region averaged about 20 percent less than in the grassland habitats on the study aren,s in ~lontan!1 and North Dakota. It should be mentioned that the grasslands on the study areas consisted of s111all tracts adjacent to crops and cut by many roads and fences. In the regular grassland region, sUlTey stops were generally remote from crops and ground disturbccl by roads Or fences.

ANALYSIS OF DATA COLLECTED IN CONNECTION WITH CONTROL SURVEYS Dl1tl1 accumulated in control surveys I1re so voluminous that it is pnLcticable to publish only a sumnul,l'Y, which will be found in table 9. • The tl1ble shows the number of survey stops made in el1ch State each yel1l' and the highest prcclfLtism foun(~ at fL single stop in efLch State. The tfLble also shows Ule l1.verage percentfLge of egg pods destroyed by each of the three predators. 'rhis is the fLvemge for fLU stops made in all counties in each Stl1te, cfLlculated from the number of pocls found I1t each stop and the number that were destroyed by each of the three predators I1t each stop. The number of pods per square foot is omitted fronl the lable, but the number found at each stop is recorded in the voluminous compilation from which the table is derived. KEY TO AB13HEVIATIONS IN TABLg 9 The abbreviations usecl in tfLble 9 to indiel1tc dominl1nt species of grasshoppers are as follows: Species: Abbm'iatfon Jfclanoplus bivillalllS (Sny) ______• __ • __ . ______bhr 11f. devastator Scuclcl. ______.... _.. ______. _____ clcy M. differentialis ('1'h08.L ______cliff Oedaleonatu,s enigma (Scudd.) ______.___ ellig "1f. !C1nur-rubrwn (DeG.) ______f-r kr. '/Iwxicanll,~ mcxicanll.s lSauss.) ______". ______•• ____ mcx • M. packardii ScuclcL ______pack 'l'rilllcrotropis pallidipcnnis 1)aliiilipcnnis (llurm.) _.. ,_ .. _" __ ___ pal Cu mmlia pcllucida (Srurlcl.) ______" ______" __ pcll Arphta 7Jseuilonielano. (Thos.) ______.. ______p8eu Aeoloplides turnblllli (Tho:3.) _____ " _. _.. _____ " ______" ______turn

• 17 TABLE 9.-SUl\BIARY OF DATA COLLECTED IN CONTHOL SUHVEYS: Grasshopper egg pods destl'oyecl by larvae of bee flies, blister beetles, • and ground beetles, by States and years

Highest Average perc.;ntagc of pods I pred- destroycd by- Dominant atism St.a.te and year Samples species 1 at any survey Bee Blister Ground All stop fly beetle beetle larvae larvae larvae lan'ae

lVU7n- Per- Per- Pcr- Per- Per­ ber First Second cent cent cent cent Arizona______645 cent 1938_____ 500 1939_____ mex pal 75 3. 6 3.1 O. 2 6. 9 145 mex diff 55 17.5 Arkansas: 8. 5 8. 2 34.2 1939_____ 1, 270 diff mex 40 5.0 3.5 .2 California____ 2, 406 8. 7 1938_____ 215 dey 194D_____ cliff 44 .4 .2 .8 1. 4, 2,191 dev enig 75 .6 1.3 I. 5 3.4 Colorado_____ 11,058 1938_____ 3,545 biv mex !J6 7.9 7.2 1.7 • 1989_____ 16.8 1940_____ 5, 596 mex turn 89 14.2 6. 5 1.0 21. 7 1, 927 turn mex 91 11. G 18.5 1.8 a9 1daho ______2,246 1938_____ 1939_____ 1, ~5a f-r mex .50 2. 2 • :3 3. 0 5.5 793 mex f-r 60 3.8 .2 0 4.0 Illinois______1,117 1938_____ 630 1939_____ f-r cliff 48 1.1. 12.9 3. 3 17. :3 487 cliff f-r 7n 3. 9 17. 9 10. 0 32. 7 10wa______4,820 1938_____ 3, 357 £-r cliff 91 .6 6. 9 1.9 9. ,1 1939_____ biy 1940_____ 865 cliff 60 . 1 10. 3 2. 6 13. 0 598 biv cliff 72 11. 7 12.7 7. 8 32. 2 Kansas ______9, 201 1938_____ 4,527 diff mex 78 2. 8 a. !J 1.0 7. 7 1939_____ 2,171 1940_____ turn mex 67 3.3 2. 7 .1 6. 1 2,503 turn mex 67 2.3 7.6 .6 10. 5 Michigan____ 3, 155 1938_____ 1,080 mex pell 78 7. 9 .2 5. 4 13.15 1939_____ 1,511 mcx 1940_____ f-r .51 3. 0 1.2 2. 0 6.2 564 mex pseu 38 1.6 0 .7 2.3 Minnesota ___ 13,074 1938_____ 3, 335 f-r cliff 83 3. 4 2. 7 1.7 7.8 1939_____ 5,367 diff 194.0_____ f-r 70 7. 3 6. 8 8. 4 22.5 4, 372 f-r biv 88 5.6 5. 7 6. 9 18.2 • MississippL __ 195 1938_____ 105 1939_____ mcx cliff 21 1. ,t 1.8 0 3.2 90 cliff f-r 40 2. 0 4. 6 0 6. 6 MissourL ____ 4,42.5 1938_____ 4,083 1939_____ mex cliff 100 0 7.1 .3 7. 4 342 mex cliff 20 2. 2 1..5 3. 7 Montana_____ 30, 905 1938_____ ° 9,360 mex pack 96 0.2 .5. 8 .3 15. 3 1939_____ IS, 255 1940_____ mex pack 88 9.7 5. 2 1.0 15.9 6,290 mex pack2 80 0. 8 4. 5 2. 3 16. 6 Nebraska ____ 24, 388 1938_____ 6,026 mex biv 78 6. 6 9.1 2. 0 17.7 1939_____ 14,.347 1940_____ cliff mex 76 6.3 9.4 .5 16.2 4,015 diff biv 86 6. 4 7. 9 .9 15. 2 See footnotes at end of table. • TABLE 9.--8Ul\ll\[ARY OF DATA COLLECTED IN CONTROL SURVEYS: Grasshopper egg pods destroyed by larvae of bee flies, blister beetles, • and ground beetles, by States and years-Continued Highest Average percentage of podfl pred- destroyed by- I Dominant atism State and year Samples! species I at any survey Bee Blister Ground All stop ilv beetle beetle larvae I lan;ae larvae larvae

Nwn- Per- Per- Per- Per- Per­ ber First Second cent cent cent cent cent K evud!L _____ 3,076 1938_____ 623 mex biv 50 15.9 O. 1 0 16. o 1039 _____ 1, 258 I 1940_____ mex bi\' 86 9.4, 2.2 .1 11. 1, 105 mex bi\r 84 14.6 . 8 .2 15. 6 New Mexico__ 1,005 1938_____ 505 mex hiv 66 2. 5 3.0 1.6 8. o 1939_____ 500 f-r cliff 82 7.4 3.1 0 10. 5 )iorth Dakotn_ 24, 51S 1938_____ 6, 886 pack 93 :30.8 9.5 1.4 41. I 1939_____ mex • 12, 730 mex biv 87 16.8 7. 6 3.1 27. i)­ 1940_____ 4, 902 mcx hiv 95 16. 0 S. 5 3.0 28. 4 Oklnhomn____ ·1,371 1938_____ 2,v35 diff mcx 84 8.1 8.6 .1. 7 21. 4 1939_____ 1, 361 mex turn 75 a. :3 9.0 .3 12. 6 1!).+0_____ 375 m('x turn !l6 3.1 :3. 0 0 7. o Oregon ______(.1+ 1038_____ 180 TIl ex pell 57 7.5 0 0 7. , 193!L___ 56·J mex f-r 87 19. a 1.S 5.2 26. : South Dnkotn_ 22,585 1938_____ 8, 225 mex cliff !l4 12.0 6.6 .9 19. 5 1939_____ 9,4!l7 TIlex cliff 83 11.8 10.5 1.7 24. o 1940_____ 4, 893 diff hiv 80 10.3 13.8 1.0 25'. 1 . Texas______7,005 1938_____ 4,190 pack 83 L3 5.4- 2. 0 8. I 1!l39_____ diff 1, 075 111 ('x cliff 60 2. 2 3. 2 2. 3 7. I 1940_____ 840 mex turn 67 .0 8. 6 . 5 10. o Utah______·J,780 ] 938 _____ 1, 550 f-r mex 6!l 8.1 3.5 10.8 22. 4 1939_____ 3,230 mex f-r 75 16.4- 2. 4 12.9 31. 7 Washington __ 453 1038_____ 240 mex [-1' 67 0 0 17. 7 17. I 193\L___ 21a mex f-r 50 12.6 1.4, 2. 3 16. 3 Wisconsin____ 20,0!l5 • 1938_____ 10,315 f-r lllex !l3 :3. 8 0 5.2 9. o 1!l3!l_____ 8,300 f-r lllex 57 .8 . 1 .!l 1. 8 1!l40_____ 1,480 f-r mex 50 .4- 0 .2 6 \Vyom~ng---- 5,204 1!l38_____ 2,555 mex bi\' 75 9.3 3. 7 2.0 15. o 1939_____ 2,:308 mex bi\' 87 16.2 7.1 2.1 25. 4 1()40_____ 3·1] bi\' I f-r 58 10.3 8. 5 .6 19..4 I See key to nbbreviations, p. 17. 2 Another species (bi\') wns equally dominant, but pack was first dominant nt 1 stop and bi\' was not recorcled as first dominant.

• 19 Several other species of grasshoppers were dominant or second dominant in a few counties but not in any State as a whole. These species and the counties and years in which they were dominant are • listed in table 10.

TABLE 10.-Species oj grasshoppers that were dominant or second dominant in individual counties but not throughout the State, by county and year

Collected in­ Species and year

S~ate County

Ayeneolettix deorwn (Scudd.): 1938______i\Iichigan ______IHontcalm, Osceola, and Wexford. 1939 ______{~~!sCchoigas~------­ l\Ianistee and Oceana. "I n In______Wood. 1940______MichignIL------Newago and Oceana. A uZocara elZiotli (Thos.): 1938_.______Wyoming------Niobrara. Kansn5______Pawnee, Rush, Seward, and • Trego. Nebraska______Rock. 1939 ______North Dnkoht__ Adams. Oklahoma______Beaver. South Dakota__ _ Harding, Lawrence, "Tash­ ington, and Ziebach. Wyoming______Crook. Nebrn5ka______Keya Paha. Oklnhomlt______Greer and Kiowa. 1940______South Dakotn__ _ Jackson, Shannon, Todd, "\Yashabaugh, and "Tash­ { ington. Texn5______Armstrong, Hemphill, and Lipscomb. Dissosleira caroUna (L.): 1938______{S\\~~sltclol Ds~kota--- Potter. I, n In______Sheboygan. 1040______Montana______Golden Valley and Hill. Dissosteira lonyipennis (Thos.): fNew ~rexico ___ _ Colfax and Union. 1938______~ Oklahoma______Cimarron. LTexn5 ______Armstrong, Briscoe, Carson, Ca.~tro, Deaf Smith, Floyd, Hunsford, Hartley, Hemp­ • hill, HO\\'ard, Hutchinson, Lamb, Lipscomb, i\{oore, Ochiltree, Oldham, Potter, Randall, Roberts, Sher­ man, and Swisher. 1939______New i\Iexico___ _ Quay. Encopl%phus sordidus sordidus (Burm.): 1938______Michigan------­ Presque Isle. ]yfelanoplus anyu sl i p e wni s (Dodge) : 1938 ______do______l'decosta. lIfelanoplus con/usus (Scudd.) : 1938______Texas______Hale. 20 • TABLE 10.-Species of gmsshoPPf'I's that wel'e dominant or second dominant in individ1wl counties but not throughout the State, by • county and year-Continued Collected in- Species and year State County

"Velanoplu,~ da1Vsoni (Scudd.) : 1939______. ______l\fin.nesota______Crow Wing and Itaskn. 194.0 ______do ______Carlton, Itaska, St. Louis, and Stenfl1s. }.Ielanoplus foed11s foedu8 Scudd.: IdahO______Boise. 1938______Oklahorna______Ellis and Pottawatomie. { Texns ______Fisher. lIfeianopl1tS lakinus (Scude!.): 1940______California______Sacramento. j\[elanoplus 1Ilar{Jinalus (Scudd.) : 1939______Arizona ______Santa Cruz. j\IelanoplllS TlI(l{Jlesi Gurney: • 19·10 ______Nevadfi ______Lander and Nye. Schislocerca a1llert"cana amer£­ cana (Drury): 1939______l\'Hs::lourL ______Pemiscot. .Mixed range: 1930______Nebraska______Cherry, Garden, Grant, and Hooker. 10·W______South DakoL1L__ Ziebach.

Figures 1, 2, and 3 show the totn.! percentn,ge of grasshopper egg poels destroyed by fiJi predators com bined, as determined in tbe sur­ veys mnde in connection with control ,,-ork in the fnil of 1938, 1939, and 1940, rcspeetiYcly. The mnps show the aYernge percelltnge of predn.tisJll for all SlllTey stops made in cneb county. For cXfHnple, 19 survey stops were mn.de in Sbcridnn County, N ehr., in 1938, and the pcrccntage of cgg pods destl'oyccl n,t ('arb of the 19 stops was 58, 78, 77,78,57,54,67,00,53, 5S, 3S, :35, (IS, 45, 23, ]8, 55, 54, Itlld 50 1Jor­ • cont, or an fl,vcmge 01 55 perccnt for the 19 sLops.

• 21 hi hi 1938

o Counties lurvlyed but no predators found ~ From I 10 24% aD From 25 10 49% _ From 50 10 14% _ 15% or more

FIGURE l.-Totlll pereentllge of grasshopper egg pods destroyed by larvae of bee flies, blister beetles, and ground beetles, autumn 1938 . • • • • • • • •

1939

o o Counties surveyed but no predators found ~ From I 10 24% D From 25 10 49% _ From 5010 74% _ 75% or more

FIGURE 2.-Totlll percentage of grasshopper egg pods destroyed by larYlie of bee flies, blister beetles, t.:l and gronnd beetles, autumn 1939. W !;:! 1940

o Counties surveyed but no predators found ~ From I to 24% l'Elll From 25 to 49% _ From 50 to 74% ~ _ 75% or more

FIGURE 3.-Total percentage of grasshopper egg pods destroyed by larvae of bee flies, blister beetles, and ground beetles, autumn 1940 . • • • • PREDATOR SPECiES AND DiSTRIBUTION RECORDS Occasionally, larvae and pupae of bee flies, blister beetles, and • ground beetles found in or near grasshopper egg pods were reared to adults and then sent to specialists for identification. Sometimes, adult bee flies and blister beetles associated with t1.dultgrasshoppers were collected by personnel making State grasshopper surveys. Some of these predators were identified as species whose grasshopper egg-pod feeding habits were known. The rearing of larvae or pupae and the collecting of adults were not adequate to establish accurate ratings of abundance or exact limits of distribution, but, the records are presented to supplement those of other workers. Bee Flies (Bombyliida,e) The distribution of species of bee flies Lhat were rem·ed from larvae or pupae found in or ncar grasshopper egg pods or were collected as adults where grasshoppers were a;bundant is shown in table II. • TABLE 11.-Dist1'ib1ltion oj species oj beejlies, by Stalf a;nd c01mly Collectcd in- Species 1------·-,------­ 1____Stl.l_t_:C_____1______C_0_ll_ll_ty_._l_____

Anasloech'lls barbaius (Osten 1\Jontan:L ______Gallatin* lwd Hill. * Sucken). C:llifornhL ____ _ Siskiyou, * J\'Iodoc, * Lassen, * Itnc! coustal areus from .I1phoebanills hirs /ltus (Coq.) ___ _ Monterey County to Sun { Diego County. Orcgon___ .______IGnmath.* A phoebant1~s 1IlUS (Osten Sack- Orcgon ______Klltmuth.* en). Aphoebantus n. sp. #L ______Colorado______Lincoln.* l1phoebantlls 11. sp. #2 ______NcvadlL ______Lander.* Systoecl!1(s oreas Osten Suckcll __ Orcgon______Klumuth.* Michignn______Otsego. Minnesota______Kittson* and Trltverse. * lVIontrlI1It______Fergus,* Hill, * und Rich­ land. Ncbrasku______Howard,* Lillcoln, * und • Sysloeclw.s vulgaris Loew______Scotts BlufY. * North Dnkota__ Billings, Golden Valley, * Gmncl Forks, ~'Iorton, * Pembina, RenYille, Itnd Stark.* South Dltkota__ Duvison* :llld Perkins.

1 An astcrisk following the nltllle of the county indicntes that larvae or pupac were collected in or ncar grasshopper egg pods and held until adults emerged. Adults of species of known grasshopper cgg-pod feeding habits were collected in the other counties listed. Systoechus 'v1llga7'is, with records of oceurrence in :Michigan, :Minne­ sota, :Montana, Nebraska, North Dakota, and South Dakota, Wll,S the most common and also the most widely distributed species. Aphoe­ bantus hirsutus was the next most common species, but its distribution was limited to Ca.lifornia and Oregon. • 25 Blister Beetles (Meloidae) The distribution of species of blister beeties that were reared from • larvae or pupae found in or near grasshopper egg pods or were col­ lected as adults where grasshoppers were abundant is shown in table 12.

J:ABLE 12.-Distribution oj species oj blister beetles, by State and county

Collected in- Species

State County 1

Epicauta collosa Lcc______{South pakota___ Custer* and Pennington.* Wyommg______Park. Epicautajerruginea (Say) ______{Iowa______.___ Dubuque. Montana______Hill. Epicauta lemniscata (F.) ______Iora______Crawford andPottawatta­ mie. Colorado______Pueblo.* Iowa______Crawford and Pottawat­ tamie.. Kansas______Cheyenne, * Greeley, Scott, * Sherman, and Wichita. * • Montana______Hill * and Pondera.* Epicauta maculata (Say) ______Nebraska______Cheyenne, * Clister, Dawes, Kimball, * and Logan. * North Dakota __ Golden Valley, * La Moure, * IJogan, * niorton, and Ward. * South Dakota__ _ Davison.* Wyoming______Park.* Epicauta oregona Horn ______:Montana ______Pondera.* Pottawattamie. Epicauta pennsylvanica (DeG')-1~1~~Ean~~~~~~~~ Hill. Nebraska______Custer and Thurston. Wyoming______Goshen. Epicauta puncticollis (Mann.) __ California______niodoe, * Sacramento, * San Diego, * San IJuis Obispo, * and SiRkivou. * Epicautasedca,ns Lec______North Dakota__ _ Logan, * McLean, * and J.\<101'­ ton.* " fC~olorado ______Lincoln.* Epzcauta. alb1da (Say) ______lKansas------Greeley. New Mexico___ _ Quay.* Montana______Fallon, * Fergus, * and \Vi­ ballx. * Minncsota______Traverse. * • Epicautajabricii (Lec.) ______Nebraska______Banner, * Custer, * Dawson, * Lincoln, * Logan, * Madi­ son, * and Valley. North Dakota__ Barnes, * La :Moure, * nle­ Intosh, and Morton. South Dakota__ _ D2ivison.* Epicauta subglabra (FalI) ______North Dakota __ :Morton* and Sioux. *

1 An asterisk following the name of the county indicates that coarctate larvae or pupae were collected in or near grasshopper egg pods and held until adults emerged. Adults of sp:Jcies of known grasshopper egg-pod feeding habits were collected in the other counties listed.

26 • Epica·uta maculata, with records of occurrence in Colorado, Iowa, Kansas, .Montana, Nebraska, North Dakota, South Dakota, and Wyoming, was the most common and also the most widely distributed • species. E. jab7'1~cii was the next most common species; it was foun d in :Minnesota, :Montana, Nebraska, North Dakota, and South Dakota. E. puncticollis, found only in California, was the only meloid egg-pod predator found in that State. Ground Beetles (Carabidae) Only a few ground beet.le larvae lLud pupae found. closely associated with grasshopper egg pods were retlred to the adult stage and identi­ fied. L. P. Rockwood of the Grasshopper Research Project reared adults of Li1;-Jal'a obesa (Say) from laTVae found feeding on Camnula pellucida. egg pods in Klamath County, Oreg. He also observed that adults of the same species dug in to O. pellucida egg beds and ate large numbers of eggs. Riley (4) stated that A. obcsa larvae destroyed large num­ bers of grasshopper eggs in Minnesota in 1876 aud 1377. As this species is widely distributed throughout the regions where grass­ hoppers are most llbundan t, it is perhaps the most important carabid • grasshopper egg-pod predator. C. C. 'Wilson of the Grasshopper Research Project reared four other species of ('ftrabidn.e-Amara imp111lcticollis (Say), Anisodactylu8 caZijOl'niCU8 (Dcj.), A. nivcdis Horn, and Plerostichus occidentalis (Dej.)-from laryae and pupae found in or near grasshopper egg pods in Sacramento Count:r, Calif.

DISCUSSION The belleficinl l'fIccts of natural factors m reducing grasshopper infestations is generally recognized. :i\[ost farmers and workers engaged in grasshopper control haye seen grasshopper populations greatly reduced by parasites and diseases; insect, hird, and animal predators; and weather. Entomologists, including the authors, have been prone to view destruction of grasshopper eggs bY' larvae of bee flies, blister beetles, and ground beetles as of importance locally but of minor and unpredictable. importance in reducing grasshopper populations oyer sizable geographical areas. Data obtained by the Plant Pest Control Division in county surveys indicate that destruction of grasshopper egg pods by these predators • was high oyer several extensive areas for the 3 years of survey, and there were few counties in which it did not ocr.lll'. For example, figure 1 shows that in 1938 from 25 to 49 percent of all egg pods were destroyed ill an area that included the eastern part of :Montana, nearly nIl of North Dakota, the western part of South Dakota, the Pan­ handle of N ebmska, alld several counties in Colorado, northern South Dakota, and western 1finnesota. ,Vithin this extensive area, preda­ tism ranged from 50 to 64 percent in single counties and groups of contiguous counties. In many counties where the average percentage of predators was high, predatism was 80 to 90 percent at individual survey stops and in a few counties, it was as much as 100 percent. Data obtained by the Entomology Research Division on smaller unit Il,reas, but by more intensive sampling over more years, are in • 27 sm-prisingly close llJ:l'eement with data obtained in the same counties by the. Plant Pest tJontrol Division (table 13). A comparison of data • from the two sources shows that in at lellst four of the Sbltes subjcct to major grasshopper outbreaks Jlln~ae of hee flies, blister beetles, Ilnd ground beetles destroy consideru.ble lllunbers of grussboppel" egg pods every yellr. In the counties listed, !l\~erngC' yeurly reduction approx­ imates 25 percent of the eggs laid . . "~jthpl1t destruction of grasshopper egg pods by lalYIlC of bee fhC's, hhster beetles, and ground beetiC's, nne! by other natural flleiors, thC' frequeucy of major grnsshopppr outbreaks o\'cr exte-Ilsi\'c areas would be- grea.tly incl·easNI. .Altogether, natural factors axe so important in pre\-enting l'xt('nsivl', explosive outbreaks thut control by man, necessary ns it is for additional populn,tion fe-(\nction and crop protect ion,_ is directed at only a smnll purt 01. the potent ial population.

TABLE 13.-Egg pods destroyed bylo/'vae oj ba flies, bliBlcr beetles, (Llul ground beetles in study o}'e(£s, as determ.ined in research 811I'l'eys, and in entire er>unties 1l'here sludy (1/'('(18 'L{,ere [Ilcaled, ({s deierminedin control SW'I'CYS •

I A \'cragc pcr­ : centngc' of cgg Survey i pods dcstroyed State and county , in- ,------_._------­ ! I Study tHea EuUre county ~ Study i Entire ! are:l i county ------I---~------,------.'---'---­ I :Ywn-! Year IjYulll-! Year Per- ! Percellt Minnesota: ber beT 1 cent ! Kittson______; 3 HJ:39-41 II 3. 1938-·10 .:. 21 I 11 .Mon tn.Tln.: I I 11111______I 7 I.1\).39-10 - 3 ! HJ3S-·10 : ')8 I 26 9 yclJowstonc______7 I'. 19;{9;. I ;) ! 1938-,10 ; 16 I HlH-'16 I Xorth Dakotlt: I I I ,....) Goldcn Vallev ______I! S . 1939-·!(j 3 I 19:38-10 I D_ _I 31 !\lortoll_____ -:.. ______• 8 I HJ39-46 jl a : 19a5-·IO I ;~ I' i Stark______l 8 19;)9-16 3 I 1938-40 28 33 South DakottL: i I I Davisoll ______! 9 j 1938-46 • 3 ; ]938-40 I 19 ' 17 • Average (WCighted)_r::·=-::=~i::~===~==tl·------: 2·1 ' 2-1 I I: . j ------~--~ -.-.------~--- LITERATURE CITED

(1) GRIDDLE, XORMAN. 1033. NOTES ON TnE HAm'rs O~' INn'lnot'S ORASSHOPPERS IN MANITOB.~. Cnn:lC1. Ent. LXV: 98. (2) GILl1ERTSON, G. L, and HORSFAf,r" '\'. R. 1940. BLISTEH BgE'rf,ES .\:-;D THEIR CONTROL. S. Dak. Agr. Expt. Sta. Bu!. 340: 20-2l. (3) HonsFALI" W. R. 1943. DIOLOGY AND CONTROl, OF CO~n!ON BLISTER BEETLES IN ARKANSAS. Ark. Agr. Expt. Sta. Bu!. 436: 16, 4.0. 28 • (4) RILEY, C. V. 1878. FIRST ANNUJ\L REPORT O~' THE UNITED STATES ENTOMOLOGICAL COllllIlSSION: 289-302. (5) 1880. SECOND REPORT O~' THE UNITED STA'l'ES ENTOlIOI,OGICAL COMMIS­ SION: 259-268. (6) SHOTWELL, R. L. 1939. 'I'HE SPECIES AND DISTRIBUTION OF GRASSHOPPERS IN THE 1939 OUTBUEAKS. U. S. Bur. Ent. und Plant Quar., Insect Pest Survey Bul. 19 (sup. 5): 190-191. (7) WII,SON, C. C. 1936. NOTES ON TUB WAumon GUASSnOPPEU, O~lAfNUJ,A. PELJ,UOIDA (~I}UD[)EU) AND, ITS E?G p~u:,"srrE A.PllOEBA.NTUS lllRSUTUS (COQ.). Jour. Econ. Eut. 29. 413-416.

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